/Engine/Source/Runtime/Core/Public/HAL/IPlatformFileCachedWrapper.h
Attempt to open a file for writing. If successful will return a non-nullptr pointer. Close the file by delete'ing the handle.
virtual [IFileHandle](API\Runtime\Core\GenericPlatform\IFileHandle) * OpenWrite ( const TCHAR * Filename, bool bAppend, bool bAllowRead )